Effects of intrauterine infection in different periods on the placenta and endometrial blood vessel formation of pregnant mice and the growth and development of fetal rats

Objective:To investigate the effects of intrauterine infection in different periods on the placenta and endometrial blood vessel formation of pregnant rats and the growth and development of fetal rats.Methods:According to the random number table method,32 pregnant rats were divided into the early infection group,the mid-term infection group,the late infection group and the control group,with 8 rats in each group.On the 3rd,9th and 15th day of pregnancy,lipopolysaccharide was injected intraperitoneally to construct intrauterine infection models.The pregnant rats in the control group were intraperitoneally injected with the same dose of 0.9%sodium chloride solution.On the 18th day of pregnancy,the inflammatory factors[interleukin-6(IL-6),tumor necrosis factor-(TNF-)],the blood vessel density of placenta and endometrium in the placental tissues of pregnant rats,dead fetus+absorbed fetus,the inflammatory factors IL-6,TNF-and oxidation reaction indicators[malondialdehyde(MDA)and myeloperoxidase(MPO)]in the fetal rat lung and brain tissues were detected.Results:The changing trend of IL-6 and TNF-levels in the placental tissues of pregnant rats with intrauterine infection in different periods was:the control group<the late infection group<the mid-term infection group<the early infection group,the differences were statistically significant(p<.05).The changing trend of fetal rat weight,placental weight and placental coefficient in the intrauterine infection groups in different periods was:the control group>the late infection group>the mid-term infection group>the early infection group,the differences were statistically significant(p<.05).The blood vessel density of placenta and endometrium,the mean number of fetuses,brain coefficient and lung coefficient in the late infection group were significantly increased in comparison with the early infection group and the mid-term infection group.The total number and the ratio of dead fetus+absorbed fetus,the levels of IL-6,TNF-,MDA and MPO in brain and lung tissues were significantly reduced,and the differences were statistically significant(p<.05).The blood vessel density of placenta and endometrium,brain coefficient and lung coefficient of pregnant rats in the mid-term infection group were significantly increased in comparison with the early infection group,and the differences were statistically significant(p<.05).There was no statistically significant difference in the other indicators between the two groups(p>.05).Conclusions:Intrauterine infection in different periods can inhibit placental and endometrial angiogenesis,and affect the survival rate of fetal rats and the growth and development of brain and lung.The reason may be related to the aggravation of fetal inflammatory responses and oxidative stress.The earlier the intrauterine infection occurs,the severer the adverse effects on the fetal rats will be.

Studies on Nutritional Effects of Traditional Chinese Tonics with Nutrients Fortification on Pregnant Women and Pregnant Rats

Objective: To explore the nutritional and health promoting effects of nutrient mixture (traditional Chinese tonics ＋ nutrient fortification). Methods: (1) One hundred and three primigravid women were divided randomly into the test group and the control group treated with nutrient mixture and vitamins respectively and the effects of treatment were observed. (2) Effects of nutrient mixture were also observed in pregnant rats. Results: (1) Clinical study showed the serum levels of iron, zinc, hemoglobin of the test group were allraised after treatment, and these parameters and the concentration of iron in umbilical cord blood as well as the weight of the new-born baby of the test group were higher than those of the control group (P ＜0. 05 or P＜0. 01). (2) Results of the experimental study showed that the food utilization rate, hemoglobin level, fetal growth and developing parameters of the test group were all higher than those of the control group significantly (P ＜0. 05 or P＜ 0. 01 ). Conclusion: The nutrient mixture has a good nutritional and health promoting effect on pregnancy.

Folic acid supplementation attenuates hyperhomocysteinemia-induced preeclampsia-like symptoms in rats

Folic acid participates in the metabolism of homocysteine and lowers plasma homocysteine levels directly or indirectly. To establish a hyperhomocysteinemic pregnant rat model, 2 mL of DL-homocysteine was administered daily by intraperitoneal injection at a dose of 200 mg/kg from day 10 to day 19 of gestation. Folic acid was administered by intragastric administration at a dose of 20 mg/kg during the period of preeclampsia induction. Results showed that systolic blood pressure, proteinuria/creatinine ratio, and plasma homocysteine levels in the hyperhomocysteinemic pregnant rats increased significantly, and that body weight and brain weight of rat pups significantly decreased. Folic acid supplementation markedly reversed the above-mentioned abnormal changes of hyperhomocysteinemic pregnant rats and rat pups. These findings suggest that folic acid can alleviate the symptoms of hyperhomocysteinemia- induced preeclampsia in pregnant rats without influencing brain development of rat pups.

Barrier Effect of Placenta Membrane of Pregnant Rat on Mixed Rare Earth Changle

To assess the potential health risks of mixed rare earths Changle for human embryo, whether it crosses placenta membrane or placenta barrier should be determined. In order to arrive at the aim placenta tissue was observed after contamination with optical and electron microscope to show distribution and destiny of mixed rare earth Changle in placenta tissue. Meanwhile the amount of rare earths in serum of pregnant rat, amniotic fluid and extract of embryo tissue were measured by using Inductively Coupled Plasma Mass Spectrometer (ICP MS). The rats were administered to 0 3, 2, 5 and 20 mg·kg -1 mixed rare earths Changle every day, respectively by oral from the 6th to 18th day after pregnancy. The results show that many particles are found in syncytiotrophoblast around capillaries of placental villi in contaminated groups under light microscope, and there are more particles following increased dose. It also was observed that some dense bodies with the envelope in placenta membrane and to difference extent damages the mitochondria crista within syncytiotrophoblast cytoplasm in contaminated groups under transmission electron microscope (TEM). Results of ICP MS assay indicate that the level of Ce increases with contamination dose in the serum of pregnant rats, and the level of total rare earth element remarkably rises in amniotic fluid and serum of pregnant rats for 20 mg·kg -1 group as compared with the control without change for the other groups.

Ototoxicity of styrene

Styrene is extensively used in industry,but its ototoxicity,in particular in the pregnant female and the offspring,is still not well understood.In the current study,young adult male rats and pregnant female rats were exposed to styrene by gavage at different doses.The young adult male rats received a total of 12g/kg styrene within different periods (800 mg/kg/day for 5 days/week for 3 weeks,400 mg/kg/day for 5 days/week for 6 weeks,200 mg/kg/day for 5 days/week for 12 weeks,and 100 mg/kg/day for 5 days/week for 24 weeks) and the pregnant female rats received styrene at a dose of 400 mg/kg/day for 5 days/week for 6 weeks starting from the gestation day-4.Hearing loss and hair cell loss were assessed 5 days after the styrene treatment in the young adult male rats and in the mother rats.The cochlear impairments in the rat pups were examined 2 months after their birth.The styrene exposure caused hearing loss and hair cell loss starting from the mid-frequency region in the third row of outer hair cells (OHCs) and the impairments appeared to be related to the dosing level in each single day.Significantly,the styrene exposure to the pregnant rats interfered with auditory functional development of their fetus,leading to a deficit of cochlear amplification,although the OHCs appeared to develop well.The results indicate that a short-term high-level styrene exposure may be more ototoxic than a long-term low-level exposure for a similar total styrene dose and the styrene in the pregnant woman’s body may interfere with auditory development of their fetus.